Very recently, molecular diagnostics has increasingly gained in importance. It has found an entry into the clinical diagnosis of diseases (inter alia detection of infectious pathogens, detection of mutations of the genome, detection of diseased cells and identification of risk factors for predisposition to a disease).
In particular, through the determination of gene expression in tissues, nucleic acid analysis opens up very promising new possibilities in the study and diagnosis of disease.
Nucleic acids of interest to be detected include genomic DNA, expressed mRNA and other RNAs such as MicroRNAs (abbreviated miRNAs). MiRNAs are a new class of small RNAs with various biological functions (A. Keller et al., Nat Methods. 2011 8(10):841-3). They are short (average of 20-24 nucleotide) ribonucleic acid (RNA) molecules found in eukaryotic cells. Several hundred different species of microRNAs (i.e. several hundred different sequences) have been identified in mammals. They are important for post-transcriptional gene-regulation and bind to complementary sequences on target messenger RNA transcripts (mRNAs), which can lead to translational repression or target degradation and gene silencing. As such they can also be used as biologic markers for research, diagnosis and therapy purposes.
Multiple sclerosis (MS) is an inflammatory autoimmune disease of the central nervous system, in which the myelin sheaths around the axons of the brain and spinal cord are damaged, leading to demyelination and scarring as well as a broad spectrum of clinical signs and symptoms. MS can be classified into different disease subtypes, including relapsing/remitting MS (RRMS), secondary progressive MS, primary progressive MS, progressive relapsing MS. The relapsing-remitting subtype is characterized by unpredictable relapses followed by periods of months to years of relative quiet (remission) with no new signs of disease activity. The relapsing-remitting subtype usually begins with a clinically isolated syndrome (CIS). In CIS, a patient has an attack suggestive of demyelination. Often CIS marks the onset of MS.
The diagnosis of multiple sclerosis usually involves analysis of different clinical data, imaging data, and laboratory data. Some patients live years with MS before receiving a diagnosis of disease.
Symptoms can be similar to other diseases and medical problems. Clinical, imaging, laboratory and radiologic data of the dissemination of MS lesions need to be obtained for a diagnosis, which can be time consuming, expensive and difficult. Testing of cerebrospinal fluid (CSF) can be performed to aid in diagnosing MS, however, this involves the unpleasant and risky procedure of lumbar puncture to obtain CSF.
Therefore, there exists an unmet need for an efficient, simple, reliable diagnostic test for MS.